module.exports = function(playerAction) {
  var random = Math.random() * 3

  if (random < 1) {
    var computerAction = 'rock'
  } else if (random > 2) {
    var computerAction = 'scissor'
  } else {
    var computerAction = 'paper'
  }

  if (computerAction === playerAction) {
    console.log("平局")
    return 0
  } else if (computerAction === "rock" && playerAction === 'paper' ||
    computerAction === "scissor" && playerAction === 'rock' ||
    computerAction === "paper" && playerAction === 'scissor') {
    console.log("你赢了")
      return -1
  } else {
    console.log("你输了")
    return 1
  }
}